This produces raw PCM audio at 31.4 KHz. When I play it back at 31.4 KHz
is sounds pretty close to the actual console I sampled. All the tools I
have to convert from 31.4 KHz -> 44.1 KHz make it sound pretty bad though.
Maybe somebody else can pick it up from here...
#include <stdio.h>
// sound.c
// version 0.0
//
// Copyright (c) 2003 Adam Wozniak (adam@xxxxxxxxxxxxxxxx)
// All Rights Reserved
//
// Permission granted to freely copy and use for any purpose, provided
// this copyright header remains intact.
// Produces 1 second of audio with a base frequency of 31400 Hz
static const int poly0[] = {
1, -1 };
static const int poly1[] = {
1, 1, -1 };
static const int poly2[] = {
16, 15, -1 };
static const int poly4[] = {
1, 2, 2, 1, 1, 1, 4, 3, -1 };
static const int poly5[] = {
1, 2, 1, 1, 2, 2, 5, 4, 2, 1, 3, 1, 1, 1, 1, 4,
-1 };
static const int poly9[] = {
1, 4, 1, 3, 2, 4, 1, 2, 3, 2, 1, 1, 1, 1, 1, 1,
2, 4, 2, 1, 4, 1, 1, 2, 2, 1, 3, 2, 1, 3, 1, 1,
1, 4, 1, 1, 1, 1, 2, 1, 1, 2, 6, 1, 2, 2, 1, 2,
1, 2, 1, 1, 2, 1, 6, 2, 1, 2, 2, 1, 1, 1, 1, 2,
2, 2, 2, 7, 2, 3, 2, 2, 1, 1, 1, 3, 2, 1, 1, 2,
1, 1, 7, 1, 1, 3, 1, 1, 2, 3, 3, 1, 1, 1, 2, 2,
1, 1, 2, 2, 4, 3, 5, 1, 3, 1, 1, 5, 2, 1, 1, 1,
2, 1, 2, 1, 3, 1, 2, 5, 1, 1, 2, 1, 1, 1, 5, 1,
1, 1, 1, 1, 1, 1, 1, 6, 1, 1, 1, 2, 1, 1, 1, 1,
4, 2, 1, 1, 3, 1, 3, 6, 3, 2, 3, 1, 1, 2, 1, 2,
4, 1, 1, 1, 3, 1, 1, 1, 1, 3, 1, 2, 1, 4, 2, 2,
3, 4, 1, 1, 4, 1, 2, 1, 2, 2, 2, 1, 1, 4, 3, 1,
4, 4, 9, 5, 4, 1, 5, 3, 1, 1, 3, 2, 2, 2, 1, 5,
1, 2, 1, 1, 1, 2, 3, 1, 2, 1, 1, 3, 4, 2, 5, 2,
2, 1, 2, 3, 1, 1, 1, 1, 1, 2, 1, 3, 3, 3, 2, 1,
2, 1, 1, 1, 1, 1, 3, 3, 1, 2, 2, 3, 1, 3, 1, 8,
-1 };
static const int poly68[] = {
5, 6, 4, 5, 10, 5, 3, 7, 4, 10, 6, 3, 6, 4, 9, 6, -1 };
static const int poly465[] = {
2, 3, 2, 1, 4, 1, 6, 10, 2, 4, 2, 1, 1, 4, 5,
9, 3, 3, 4, 1, 1, 1, 8, 5, 5, 5, 4, 1, 1, 1,
8, 4, 2, 8, 3, 3, 1, 1, 7, 4, 2, 7, 5, 1, 3,
1, 7, 4, 1, 4, 8, 2, 1, 3, 4, 7, 1, 3, 7, 3,
2, 1, 6, 6, 2, 2, 4, 5, 3, 2, 6, 6, 1, 3, 3,
2, 5, 3, 7, 3, 4, 3, 2, 2, 2, 5, 9, 3, 1, 5,
3, 1, 2, 2, 11, 5, 1, 5, 3, 1, 1, 2, 12, 5, 1,
2, 5, 2, 1, 1, 12, 6, 1, 2, 5, 1, 2, 1, 10, 6,
3, 2, 2, 4, 1, 2, 6, 10, -1 };
static const int divisors[] = {
1, 1, 15, 1, 1, 1, 1, 1, 1, 1, 1, 1, 3, 3, 3, 1 };
static const int *polys[] = {
poly0, poly4, poly4, poly465,
poly1, poly1, poly2, poly5,
poly9, poly5, poly2, poly0,
poly1, poly1, poly2, poly68 };
// structure to hold state information, so successive calls to TIAfill
// will not sound poppy. Be sure to clear everything to zero when changing
// C or F
struct state
{
int offset, count, f;
char last;
};
static void TIAfill(int F, int V, int C, char *buf, int size, struct state *s)
{
int value;
while (size)
{
s->f++;
if (s->f == divisors[C] * (F+1))
{
const int *poly = polys[C];
s->f = 0;
s->count++;
if (s->count == poly[s->offset])
{
s->offset++;
s->count = 0;
if (poly[s->offset] == -1)
{
s->offset = 0;
}
}
s->last = ! (s->offset & 0x01);
}
*buf = s->last ? (V << 3): 0;
buf++;
size--;
}
}
void main(int argc, char **argv)
{
char buf[31400];
struct state s;
int i;
// be sure to reset s to all zeros whenever C, F, or V change
s.offset = 0;
s.count = 0;
s.last = 0;
s.f = 0;
// usage
if (argc != 4)
{
fprintf(stderr, "Usage: %s <F:0-31> <V:0-15> <C:0-15>\n", argv[0]);
exit(-1);
}
// fill a buffer
TIAfill(atoi(argv[1]),
atoi(argv[2]),
atoi(argv[3]),
buf, sizeof(buf), &s);
// write it to stdout
write(1, buf, sizeof(buf));
}
--
adam@xxxxxxxxxxxxxxxx http://cuddlepuddle.org/~adam/pgp.html
Will code for food. http://cuddlepuddle.org/~adam/resume.html
"The dinosaurs are not around today because they did not have a space program."
-- Arthur C. Clarke
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